Turbulence enhancement of a fan array wind generator using geometric texturing and optimization-based control

TL;DR

This paper explores how geometric texturing and optimization control of a fan array can enhance turbulence, balancing between uniformity and intensity for wind energy applications.

Contribution

It introduces a novel experimental approach combining geometric texturing and particle-swarm optimization to control turbulence in fan arrays.

Findings

Checkerboard pattern yields uniform turbulence (Tu ~ 0.14).

Optimization achieves higher turbulence (Tu ~ 0.28) but reduces uniformity.

Trade-off identified between local turbulence maximization and global uniformity.

Abstract

Fan array wind generators (FAWG) are designed to generate a rich set of turbulent flows reminiscent of those found in natural environments. In this study, we experimentally investigate a square FAWG consisting of 10x10 individually controllable fans with 4 cm width and a maximum velocity of 17 m/s. The goal is to maximize the turbulence intensity in the test region. Two approaches for fan operation are investigated: first, geometric texturing of the duty cycle distribution, and second, maximization of the turbulence intensity at selected hot-wire sensors with particle-swarm optimization. We find that geometric texturing (specifically a checkerboard pattern) yields a robust, uniform turbulence field (Tu ~ 0.14) driven by jet interactions. Conversely, particle swarm optimization achieves higher local turbulence (Tu ~ 0.28) but significantly sacrifices spatial uniformity. This study underscores the trade-off between local maximization and global uniformity in active turbulence generation.